The present invention relates generally to the field of bonding of substrates. In particular, the invention relates to methods of fabricating MEMS (Micro-Electro-Mechanical Systems) and other devices which enable the operability and/or longevity of the devices.
MEMS and other devices often include two or more substrates either in close proximity or bonded together. For example, in optical systems such as digital projectors, a device may include an interference-based digital light display (DLD) package which includes two or more substrates to direct light to and from the DLD. Similar to a CRT, in a rear-projection television, a DLD can be used in digital projectors for processing or generating an image from a source light.
One such DLD package is illustrated in FIG. 1. The package 100 includes a base substrate 120 with a driving electrode (not shown), a pixel plate 110 which can move vertically, and a thin protective substrate or membrane 130. In this arrangement a reflective coating is provided on the pixel plate 110, and a partial reflective coating 131 is provided on the bottom surface of the membrane 130. The protective membrane 130 encloses a cavity in which the DLD pixel plate 110 is enclosed and allows light to pass therethrough.
To ensure reliability of the DLD package, the cavity must be essentially free of contaminants and, in particular, essentially free of moisture. In this regard, such DLD packages are generally formed in a highly controlled environment so that moisture in the cavity is minimized. However, these methods can substantially increase the manufacturing costs of the DLD package.
Thus, it is desirable to provide a reliable and inexpensive method and system of assembling such packages so that the effect of the contaminants is minimized and the prolonged operation of the DLD package is promoted.